Young thief steals show in heart-wrenching 'Sister' ★★★ 1/2

For 12-year-old Simon, the resilient central character in the Swiss drama "Sister," the ski season is a time of particular purpose. His daily gondola-lift rides to a tony mountaintop resort are not about sport but a matter of enterprise, a way of surviving.

In the rarefied air of leisure and wealth, Simon (Kacey Mottet Klein) is a skinny stealth figure, and back in the lower altitudes he's an assured salesman, hawking the gear he's stolen to neighborhood kids. Mike, a British seasonal worker (Martin Compston) from the resort restaurant who catches him, is dumbfounded to learn that Simon's escapades aren't the thrill rides of a bored kid; it would be easier to dismiss him as a smart aleck having fun. But Simon steals out of need.

The particulars of that need emerge in bits and pieces, emotional land mines that detonate with understated power in writer-director Ursula Meier's incisive and economically told film. ("Sister" is Switzerland's submission to the Academy Awards' foreign-language category.)

More or less unprotected, Simon has taken on the role of protector. Louise (Lea Seydoux), the older sister he lives with in a strikingly isolated apartment tower, is as scattered as he is methodical. She leaves him alone on Christmas to be with the latest in an apparently long string of uncaring men.

Simon has an eagle eye not just for untended possessions but for the behavior of people with money. When not stealing from them, he's playing the part of big shot. Drawn to the cool maternal ministrations of an Englishwoman (Gillian Anderson) who's on holiday with her young children, he insists on picking up the lunch check.

Mottet Klein, whose first role was in Meier's debut feature, the modernist parable "Home," brings ferocious comic poignancy to the tough-vulnerable Simon, whether he's assuming the idle pose of a vacationing European or using cigarette filters as earplugs when Louise brings her boyfriend home for the night.

The chemistry between the two leads is a razor's-edge dance: feral, childish, tender and always complex. Seydoux, seen last year in "Farewell, My Queen," is a screen presence of remarkable earthiness who makes Louise's wounds fully felt without defining them.

Meier and cinematographer Agnes Godard make potent use of the setting's highs and lows, delivering a jolt of heartbreaking hope in the film's final image.